Stung by criticism from federal judges, property-rights advocates and environmentalists, the Bush administration today plans to propose allowing salmon produced in hatcheries to boost struggling wild populations -- some to the point they could lose federal protections.

The decision is bound to set off another round of lawsuits over one of the prickliest and most complicated factors in struggles over how to restore the iconic salmon of the Pacific Northwest.

But it may satisfy Native American tribes, who say hatcheries could help wild salmon rebound if the rivers where both kinds of fish live are protected. The policy foresees allowing Native Americans and others to keep catching hatchery-produced fish so long as they're not needed to help wild stocks rebound.

The approach federal officials are unveiling is one that independent scientists tapped by the administration for advice have recommended against -- but which federal officials say they had to adopt under previous court rulings.

The policy, however, does not remove any of the 26 West Coast salmon species from protection under the Endangered Species Act, as some environmentalists predicted it would. The administration actually is proposing to increase the number of protected stocks to 27.

"This is an evolutionary approach that we think makes it possible for us to save wild salmon runs," said Conrad Lautenberger, administrator of the National Oceanic and Atmospheric Administration. "The goal is recovery of naturally spawning salmon runs."

Hatchery fish are much less genetically varied than their wild counterparts, in part because relatively few hatchery fish are used to produce the eggs and sperm needed to launch a new class of fish each year. Scientific studies have long shown that the way most hatcheries are run, the fish produced tend to harm wild stocks in ways such as crowding them out and eating their food.

"This is something every competent scientist agrees on," said Ransom Myers, a leading fish researcher tapped to advise the Bush administration. He and his colleagues on the six-member panel appointed by the National Marine Fisheries Service, a NOAA agency, advised the government not to include hatchery-produced fish among those that are protected.

But the Bush administration says properly run hatcheries could help supplement wild populations, so long as care is taken. So, the policy says, they too can be protected if their genes are no more than "moderately divergent" from wild fish.

"There are instances where hatcheries can provide a benefit, at least in the short run," argued Bob Lohn, the fisheries service's Northwest administrator. He cited the case of the White River in the southern Puget Sound area, where the population of chinook had dropped to fewer than 50 in the 1970s, but now -- thanks to supplementation by a hatchery -- numbers about 1,000 salmon returning each of the past two years.

Lohn acknowledged, though, that the science behind using hatcheries to restore wild run is "largely unproven and unknown." That doesn't mean it can't be done, he said.

Hatcheries originally were conceived as a way to make up for overfishing. Only later did their harmful effects on wild populations become clear, and then only after careful scientific study.

Said Jim Lichatowich, another member of the fisheries service's science advisory panel: "It appears to me we are making the same mistake as in the past: We're embracing this as a solution without having the knowledge and the science to determine if (hatcheries) behave the way people believe they will."

The rewrite of the policy stemmed from a decision in an Oregon court case brought by property rights advocates.

The new policy "sounds like an end run around the Endangered Species Act and the (Oregon) decision," said Timothy Harris, general counsel of the Building Industry Association of Washington, which has played a key role in fighting salmon protections. "There's no way they can legally do this."

Environmentalists fear that if hatchery fish are included among those that are protected, salmon will be so numerous that they will lose protections under the Endangered Species Act.

"It doesn't get us to the end result of self-sustaining, harvestable populations in our streams," said Nicole Cordan, policy and legal director of Save Our Wild Salmon, a coalition of environmental and fishing groups. "They're setting up a situation where you could easily make a call (that) 'These fish are fine.' "

If that happens, protections for fish such as requiring water to be left in streams and prohibiting streamside logging could be lost, environmentalists fear.

The administration's proposal comes almost a month after a key five-point portion of a draft of the policy, leaked to The Washington Post, set off a firestorm of protest from all concerned. Although Bush administration officials portrayed the 17-page policy to be proposed today as far kinder to wild salmon stocks than envisioned by those who attacked the leaked draft, the key five points are largely the same.

Lautenberger promised that the Bush administration would not use the new policy to get rid of policies protecting rivers where salmon spawn.

"Habitat is a factor, and there's no getting around it," he said. "There's no ducking the issue."